you know have you gone underwater into a diving spot and wanted more to do and to see well i have a quick suggestion that i hope you like i will be stating some underwater biomes,structures,and more that i personally would be key to a better underwater adventure because the underwater is BLAND AND BORING!!!
coral reefs:
you know a classic coral reef (with magic coral that when broken can become potion material for underwater breathing potions) with colorful fish and sunken treasure along with dangerous underwater bosses(possibly) and an abundance of sealed chests
Abandoned sunken cities:
an abundance of sunken buildings that have been worn down buy the pressure of water
can contain
regular chests
potion items
sharks
water currents
you know just somefast moving water that carries strong pressure that can deal damage and or can push the player far distances
seaweed forests
a variety of seaweed that has grown at the sea floor and has sunken ships tangled in its vines!
underwater caves
you know just some underwater caves that contain sealed chests and regular chests
new enemys
you know under water enemies havent really gotten much though and i feel like i could help with that so here are some that i think would be cool
magic imbued sharks(probably more fit for dark sea exploration
barracudas
angler fish
giant squids
you know just some basic enemies
under water bosses
you know obublu or what ever its name is and white eyes/giant white eyes
we only have 2 types of under water bosses compared to the abundance of bosses we have on land so here are some underwater based creatures i feel like would fit for the underwater aspect of adventure(mostly just boat pve bosses since heat-based magics have disadvantage compared to cold based magics and other classes)
giant variations of fish that become hostile because of magic toxifcation( basically giant fightable fish you can get from fishing)
atlantean bosses(that arent level 1000+)
Mermaids
you know?
my reason for this is probably what alot of people think
under water exploration is too BORING BLAND ABSOLUTELY HORRENDOUS compared to the exploration aspects of on land would you agree?
i will also expand on these suggestions on seperate suggestions so i can explain more in detail